Montana Title 75. Environmental Protection § 75-7-202. Definitions

(1) “Lake” means a body of standing water and the area within its lakeshore occurring naturally rather than by virtue of constructed impoundments (although a natural lake whose level is raised and whose area is increased by the construction of impoundments includes the additional level and area), having a water surface area of at least 160 acres for at least 6 months in a year of average precipitation as such averages are determined by the United States geological survey, not used exclusively for agricultural purposes, and navigable by canoes and small boats.

(2) “Lakeshore” is the perimeter of a lake when the lake is at mean annual high-water elevation, including the land within 20 horizontal feet from that high-water elevation.

(3) “Local governing body” or “governing body” is that unit of local government authorized to administer the Montana Subdivision and Platting Act on the land adjoining a lake or part of a lake subject to this part.

(4) “Mean annual high-water elevation” is the mean average of the highest elevation of a lake in each of at least 5 consecutive years, excluding any high levels caused by erratic or unusual weather or hydrological conditions. A highest elevation caused by operation of a dam or other impoundment counts toward the establishment of the mean annual high-water elevation.